Rokku staa (ロックスター)
The word 'rock star' was borrowed from English in Japanese and so mimics its pronunciation. The word isロックスター (rokkustaa).
岩 (iwa) is like a small rock and 石 (ishi) can be used for small stones, jewels or gems.
star = 星 (hoshi)
Hoshi (星)
岩 Iwa
石 ishi.
岩
The answer is rock Rock Star Rock Garden Bed Rock
nagare boshi
Party Like A Rock star
Hoshikuzu
"Hoshi" is Japanese for star. In Japanese language there is no difference between a singular and a plural. So star and stars translation is the same = hoshi.